Touch sensitive devices have become increasingly popular in electronic devices due to their ease of use, their versatility of operation, and their ability to be integrated into an electronic device. Computer monitors, laptop and notebook computers, smart telephones, tablet computers, and portable media players are equipped with touch sensitive devices that are configured to sense touch as a user input. The touch may be sensed in accordance with one of several different touch sensing techniques, including, but not limited to, capacitive touch sensing.
In some instances, a touch sensing device can detect touch with a capacitive sensing device. A capacitive sensing device can be small, for example, when included in a track pad. In a touchscreen, the capacitive sensing device can be larger. Typically, a device controller or integrated circuit is connected to a capacitive sensing device to control the operations of the capacitive sensing device. Users expect a larger touch sensitive device to be as sensitive to touch as a smaller touch sensitive device. However, it can be challenging to control a large capacitive sensing device with one device controller. This can be due, in part, to the finite number of connections the device controller has to connect to the various signal lines used to control or operate the capacitive sensors of the touch sensitive device. For example, in some embodiments, each capacitive sensor in a capacitive sensing device can be formed at the intersection of a drive line and a separate sense line. The drive and sense lines are connected to the device controller, thus requiring multiple connections. Further, a shield in the capacitive sensing device may need to have a signal repeatedly applied to it during scanning operations. The signal applied to the shield can be produced by the device controller. Likewise, other components in the capacitive sensing elements may require control signals to operate, and these control signals may be generated by the device controller.